Add FbTelemetry public class with ActivitySource and Meter names

Expose the telemetry source names as public constants so consumers can
easily subscribe: builder.AddSource(FbTelemetry.ActivitySourceName) and
builder.AddMeter(FbTelemetry.MeterName). Internal code updated to use
the constants.

Author: fdcastel

src/FirebirdSql.Data.FirebirdClient/Metrics/FbMetricsStore.cs

@@ -5,6 +5,7 @@
 using System.Linq;
 using System.Reflection;
 using FirebirdSql.Data.FirebirdClient;
+using FirebirdSql.Data.Trace;
 
 namespace FirebirdSql.Data.Metrics
 {
@@ -17,7 +18,7 @@ internal static class FbMetricsStore
 
 		static readonly string Version = typeof(FbMetricsStore).Assembly.GetCustomAttribute<AssemblyInformationalVersionAttribute>()?.InformationalVersion ?? "0.0.0";
 
-		internal static readonly Meter Source = new("FirebirdSql.Data", Version);
+		internal static readonly Meter Source = new(FbTelemetry.MeterName, Version);
 
 		static readonly Histogram<double> OperationDuration;
 		static readonly Histogram<double> ConnectionCreateTime;

src/FirebirdSql.Data.FirebirdClient/Trace/FbActivitySource.cs

@@ -13,7 +13,7 @@ internal static class FbActivitySource
 	{
 		static readonly string Version = typeof(FbActivitySource).Assembly.GetCustomAttribute<AssemblyInformationalVersionAttribute>()?.InformationalVersion ?? "0.0.0";
 
-		internal static readonly ActivitySource Source = new("FirebirdSql.Data", Version);
+		internal static readonly ActivitySource Source = new(FbTelemetry.ActivitySourceName, Version);
 
 		internal static Activity CommandStart(FbCommand command)
 		{

src/FirebirdSql.Data.FirebirdClient/Trace/FbTelemetry.cs

@@ -0,0 +1,41 @@
+/*
+ *    The contents of this file are subject to the Initial
+ *    Developer's Public License Version 1.0 (the "License");
+ *    you may not use this file except in compliance with the
+ *    License. You may obtain a copy of the License at
+ *    https://github.com/FirebirdSQL/NETProvider/raw/master/license.txt.
+ *
+ *    Software distributed under the License is distributed on
+ *    an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, either
+ *    express or implied. See the License for the specific
+ *    language governing rights and limitations under the License.
+ *
+ *    All Rights Reserved.
+ */
+
+namespace FirebirdSql.Data.FirebirdClient;
+
+/// <summary>
+/// Provides the names of the ActivitySource and Meter used by the Firebird ADO.NET provider
+/// for OpenTelemetry integration.
+/// </summary>
+/// <remarks>
+/// To subscribe to Firebird traces, use:
+/// <code>builder.AddSource(FbTelemetry.ActivitySourceName)</code>
+/// To subscribe to Firebird metrics, use:
+/// <code>builder.AddMeter(FbTelemetry.MeterName)</code>
+/// </remarks>
+public static class FbTelemetry
+{
+	/// <summary>
+	/// The name of the <see cref="System.Diagnostics.ActivitySource"/> used for distributed tracing.
+	/// Use with <c>TracerProviderBuilder.AddSource()</c>.
+	/// </summary>
+	public const string ActivitySourceName = "FirebirdSql.Data";
+
+	/// <summary>
+	/// The name of the <see cref="System.Diagnostics.Metrics.Meter"/> used for metrics.
+	/// Use with <c>MeterProviderBuilder.AddMeter()</c>.
+	/// </summary>
+	public const string MeterName = "FirebirdSql.Data";
+}